Mission
This is an odd mission in that it is difficult to do the things you are
supposed to do and still win. It is much easier to ``cheat'' and skip a
few steps. I'll describe both ways.

The right way: kill off the enemy infantry at your starting position and
then head north to the northwestern corner. There you'll find a radar
installation and a power station. Defeat the enemy infantry guarding the
spot, and capture both buildings. The radar will show you the location
of the GDI base and the UFO. Notice the truck next to the UFO. It contains
cargo from the UFO, and you will need to capture that cargo. Sell off the
power station and radar installation for more infantry, and then make for
the UFO.

Head south back the way you came until you hit the railroad tracks. Follow
the southern tracks east until you hit a dead end and then move north and
follow the other tracks. By doing this you'll avoid a titan, but you still
might run into an infantry patrol. You'll next run into two wolverines
which you can kill, and then you should head east. A train station will
be highlighted, and you'll see that the truck has made its way to Vega's
train and is unloading the cargo. Ignore it for the moment and send the
remaining engineer into the UFO. GDI might have received a MCV by this
point, and, if so, there might be a base and a couple of titans nearby.
You'll probably have to kill one of the titans to clear the way for the
engineer.

The engineer will learn that the Tacitus is gone, and so you'll have to
stop Vega's train. Don't follow the train tracks; that won't give you
enough time. Instead head south and a little west until you see the broken
bridge where the southern train tracks ended before. Southwest of that
is the back door into Vega's base, and you can move your troops inside
and kill the train. It will leave behind a crate which you should pick
up to finish the mission.

Quick method: at the start, when you see the train, have the two buggies
and the cycle attack it. They won't kill it, but they'll follow it. The
train stops in three places: once to load the cargo, once before entering
Vega's base, and once inside the base. Most of the time the vehicles will
destroy the engine at the second stop, but if not they can finish it off
inside the base. There's no need to send the engineer to the UFO.